Can't get the most basic commands to work

[Adam Wasilenko]

I am banging my head against the wall trying to get somewhere with modbus.

I have an inverter (Schneider XW+) and a communication "combox" that acts as the modbus tcp bridge to the inverter. Inverter is address 10.

Here is my code:

from pymodbus.client.sync import ModbusTcpClient as ModbusClient


client = ModbusClient('10.0.0.14', 502)
client.connect()


result = client.read_holding_registers(10,10)
print(result)
##client.close()

Modbus Error: [Input/Output] Modbus Error: [Invalid Message] Incomplete message received, expected at least 8 bytes (0 received)
>>> client.is_socket_open()
False
>>> client.connect()
True
>>> client.is_socket_open()
True
>>> client.read_holding_registers(10,10)
ModbusIOException()
>>>

Now in a desperation I started downloading freeware and got some numbers to show up in this modbus poll program: https://www.modbustools.com/download.html

It said it connected, it didn't work if the address wasn't 10, I have some confidence some communication was happening. 

Where do I go from here?

[sanju dhoomakethu]

You are missing the device address information in the read_holding_register request.

Try 

client.read_holding_registers(10,10, unit=<unit-address>)

Also please enable the debug logs so that we know what exactly is happening.

import logging

logging.basicConfig(level=logging.DEBUG)

log = logging.getLogger(__name__)

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[Adam Wasilenko]

Alas, data! I'm not even mad I wasted half a day on this anymore. Thank you Sanju!!!!!!